The 28-year-old, who finished in a tie for fourth at the Irish Open, made hay in the early-morning sunshine with five birdies before his single bogey arrived on the 18th.

“It was playing as easy as it’s going to play all week this morning so I knew I was going to have to go out and take advantage of it,” former University of Minnesota student Van Rooyen told reporters.

While today’s top golfers are hard on strength and conditioning — Van Rooyen said he also trains his eyes, working with ‘eye coach’ and fellow South African Sherylle Calder to help him around the greens.

Calder, nicknamed the ‘Eye Lady’, has also worked with the England rugby team and Mercedes F1 driver Valtteri Bottas and will be joining Van Rooyen at Carnoustie for his second round on Friday and most likely through the weekend.

“She has had a very big impact on me since I started working with her about a year ago,” Van Rooynen said.

“Putting was one of the things I knew I needed to work if I wanted to be in these positions. She has been massive.

“For me it’s about the putting stroke, but also what I see on the green. She has a program called EyeGym that exercises your eyes and helps you judge distance and have better depth perception. It’s been great.”

Van Rooyen says he would like to emulate compatriots Ernie Els, champion in Lytham in 2012, and Louis Oosthuizen, who triumphed at St Andrews two years later, but admits he has never met South African great Gary Player.

“The guy I really grew up watching was Ernie. And to see Louis come through and fulfill his potential was cool for me as a South African.

“We look up to them and try to follow in their footsteps.”

The savanna-like conditions on the course baked by weeks of above average temperatures was clearly agreeable to the South African contingent in the opening round, with last week’s Scottish Open champion Brandon Stone winner also starting well.

He was three-under after 16 holes of his round, as was Zander Lombard after his firs six holes.